My 1996 Grand Prix 3100 (just broke 100 000 kms) used to get around 10-11 kms per liter. I haven't checked it in over 18 months. I checked yesterday and I am only getting 6-7 kms per liter now.
My question is what to change first. I was planning on doing the plugs anyway, but what else has an impact on mileage that I should also change?